Safety-stop for elevators.



L- OTTO SAFETY STOP FOR ELEVATORS.

APPLICATION FILED MAR. 24, 191 1.

Patented Apr. 30, 1918.

2 SHEETS-SHEET I.

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SAFETY STOP ron ELEVATORS.

APPLICATION FILED MAR- 24.1917- I 1 @6%8%7 Patented; Apr. 30,1918.

2 SHEETS-SHEET 2- INVENTOH ATTOR N EY JOHN OTTO, OF CHICAGO, ILLINOIS.

SAFETY-STOP ron ELEVATORS.

Specification of Letters Patent.

Application filed March 24, 1917. Serial No. 157,179.

To'aZZ whom it may concern:

Be it known that I, JOHN OTTO, a citizen of the United States, residing at Chicago, in the county of Cook and State of Illinois, have invented certain new and useful Improvements in Safety-Stops for Elevators,

mally maintained out of engagement with the stop by the upward pull of the lifting cables attached to the car.

With. the above as the principal object in view, the invention consists in the novel construction, combination, and arrangement of parts hereinafter described, pointed out in the appended claims, and illustrated in the accompanying drawings, in which Figure 1 is a vertical transverse section through the center of the upper portion of theelevator car with the improved safety stop in position thereon,

Fig. 2 is a plan view partly in section of a portion of the car and safety stop mech. a nism,

Fig. 3 is a view similar to Fig. 1 showing the stop mechanism in operation and supporting the car against downward move, ment,

Fig. 4 is a perspective view of a detail of the invention.

In the drawings, 10. indicates an elevator car of the usual construction, movable vertically in a shaft 11. A cable 12 is attached to the top of the car and serves to raise and lower the car in the shaft. The cable 12 is attached to a block 13 supported above the top of the car in the center thereof by means of four parallel rods 14 bolted to the top of the car and rising vertically thereover. In the present instance two plates 15 in parallel relation are secured to the top of the block 13 and extend at their ends beyond the sides thereof. Like plates 16 are fastened to the bottom of the block under the plates 15 and through the projecting ends of these plates are formed openings for the passage of the rods 14. Surrounding each rod l-il between the upper plates 15 and heads 17 on the upper ends of the rods are coil springs 18 by means of which the car is yieldingly supported and which should the cable 12 break, or he suddenly released, will force the block 13 downwardly and cause the stop mechanism to operate in the manner hereinafter described.

Fixed against each side wall 19 of the shaft 11 in the center line of the elevator car 10 is a rack 20 extending from the top to the bottom of the shaft, each rack meshing with a gear wheel 21 journaled in brackets bolted to the side and'top of the car 10 at the upper corners thereof, the gear wheels 21 extending through slots 23 in the sides of the car. Upon each side of the gear wheel 21 concentric therewith is an elongated hub 24 from the peripheries of which hubs there project a plurality of tangential lugs or teeth 25 adapted to be engaged under certain conditions by upwardly projecting fingers 26 formed on the lower terminals of sliding stops 2?, the upper ends of which stops are connected to the lower ends of chains, cables or other flexible connectors 28 that pass upwardly through openings 29 in the top of the car and are attached to the outer ends of'the plates 15. Each stop 27 is supported upon an inclined plate or slideway 30 fastened at its upper end to the top of the car and extending downwardly and outwardly at an angle toward the side thereof, the lower end of said plate or guide way being curved and having a longitudinal slot 31 formed therein below the stop 27 through which slot a hook 32 extends downwardly from the stop and has connected thereto one end of a spring 83, the opposite end being attached to the side of the car. These springs tend normally to draw the stops downwardly and their fingers into position to en gage the lugs or teeth 25 on the hubs 2a and stop the rotation of the gears 21 and the downward movement of the car 10. The fingers 26, however, are maintained out of the path of movement of the teeth 25 by the chains 28 and only when said chains are loosened can the stops 27 be drawn into engagement with the teeth 25 by the Springs 33.

Pivotally connected to the front end of the block 13 above the elevator car are the upper ends of two lever arms 34, these arms Patented Apr. so, rare.

being journaled on a common pin 35, and

. tween horizontal rollers 40 which support the arms and serve to guide them in their longitudlnal movement.

In front and in rear of each rack and I in line with the lever arms 34 are vertical ratchet bars 41 secured to the side walls 19 of the elevator shaft and adapted to engage the toes 38 on, the lever arms when the car is to be locked against downwardly movement. The ratchet bars 41 are provided on their sides facing the car 10 with angular teeth 42, the upper sides of the teeth being horizontally disposed to provide a firm engagement therebetween and the toes of the lever arms 34.

In use, the attachment is applied to an elevator as shown in Figs. 1 and 2 and under normal conditions the parts will be retained in the position shown in Fig. 2, that is to say, the block 13 will be raised a short distance above the top of the elevator, thereby placing the springs 18 under compression. The chain 28 by this movement of the block will also be drawn upwardly and cause the stops 27 to move beyond the teeth ,or lugs 25 on the hubs of the gear wheels 21. By the upward movement of the block 13 the lever arms 34 pivoted thereto will also be raised a short distance and their lower ends travelslacking the chains 28 and ing between rollers 40 drawn inwardly,

thereby freeing the toes 38 from any chance of engagement with the teeth 42 of the ratchet bars 41. As the car is raised and lowered, the gear Wheels 21 rotate freely but if through some accident the cable 12 is broken or suddenly released, the springs 18 "will immediately force the block 13 downwardly upon the top of the car, thereby permitting the springs, 35 to draw the stops 27 downwardly so that the fingers 26 thereon will engage with the teeth 25. on the hubs 24 and tend to stop. the rotation of the gear wheels and the downward movement of the car. At the same time the pivot pins 35 of the lever arms 34 moving downwa'rdly'with the block 13 forces outwardly beyond the sides of the car 10, the lower ends of said lever arms to such a distance that the toes 38 thereon will be forced into engagement with the ratchet bars 41 and the teeth thereon looking with said toes positively stop the downward movement of the car before the same has attained a greatly increased speed. The car will thus be held against falling until the cable 12 has been fixed or a temporary cable secured to the block 13 and the latter lifted again into position shown in Fig. 1.

lVhat I claim is:

1. In a safety stop for elevators, the combination with a car and a lifting cable for said car, of a block secured to the lower end of the cable and movably connected to said car, guiding means attached to the top of the car for directing the movement of said block in a vertical direction, rack bars connected to the sides of the elevator shaft, gear wheels pivotally mounted in the top of the car in engagement with said rack bars and having laterally extending hubs, teeth projecting from the hubs of said gear wheels, stops on each side of said ear, each stop adapted to normally engage a tooth projecting from the hub of the gear wheel on the same side, a spring connected to each of said stops for holding it in engagement with said tooth, a slideway for supporting each of said stops, and flexible connections between the stops and the block.

2. In a safety stop for elevators, the combination with a car and a lift cable for said car, of a block secured to the lower end of the cable and movably connected to the ear, guiding means attached to the top of the car for directing the movement of said block in a vertical direction, resilient means connected to said guiding means and tending at all times to force the block in a downward direction, rack bars connected to the sides of the elevator shaft, gear wheels pivotally mounted in the top of the car in engagement with said rack bars and having laterally extending hubs, teeth projecting radially from said hubs, an inclined slideway below each of said hubs, the ends of said slideways being connected to the top and the adjacent side walls of the car, the lower end of each slideway being curved under the hub, a locking stop mounted on each slideway and adapted to engage the teeth of the hub above the same, a flexible connection between each locking stop and said block, and a spring connected to each locking stop for normally maintaining said stop in engagement with a tooth on said hub.

In testimony whereof I afiix my signature in presence of two witnesses.

JOHN OTTC).

Witnesses:

ANTON PIKSA, P, B. JANvEsKY.

" Copies'of this patent may be obtained for five cents each, by addressing the Commissioner of Patents.

Washington, D. C. 

